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Code migration guide

MQL4 to thinkScript converter

MQL4 indicator calculations can often be expressed as a thinkScript study, but Expert Advisor execution, terminal state, files, and ticket management must be removed or reduced to chart signals and simulated strategy orders.

Open the thinkScript Coding AgentReview thinkorswim AI Coding Agent

Generate a thinkScript draft, then save and test it in the thinkorswim editor as the intended study or strategy.

Conversion map

What changes between MetaTrader 4 and thinkorswim

The migration is a model translation. Use this map to decide where the source behavior belongs before writing target syntax.

Source and target platform conversion map
ConcernSource modelTarget modelMigration decision
LifecycleExpert Advisors and indicators respond to predefined callbacks such as OnInit, OnTick, and OnCalculate.Declarative expressions are evaluated over chart data; studies, strategies, scans, and watchlist columns have different contexts.Choose when each MetaTrader 4 calculation should run in thinkorswim; matching syntax alone does not preserve timing.
Market data and historyPrice series use terminal arrays and shift-based access; indicators commonly expose calculated values through buffers.Definitions and plots form time series and access prior values with bracket indexing or recursive definitions.Recheck bar indexing, warm-up requirements, timeframe requests, and behavior on an unfinished bar.
Indicators and chart outputCustom indicators bind buffers, while built-in indicator functions can return values directly for a requested shift.Studies use def, plot, painting, and built-in study functions to render chart analysis.Map calculations before recreating plots, labels, colors, and platform-specific drawing objects.
Orders and positionsClassic trade functions such as OrderSend work with order tickets, lots, prices, stops, and a shared order pool.Strategies use AddOrder to add simulated orders to charts; platform conditional orders are a separate workflow.Define fill timing, sizing, pyramiding or hedging, stops, and position ownership for the target platform.
Native validationCompile the .mq4 file in MetaEditor, attach it in MetaTrader 4, and test the correct EA or indicator artifact.Paste into thinkScript Editor, save it as the correct study or strategy, add it to a chart, and inspect plots or the strategy report.Treat generated thinkScript as a draft until it passes the target editor, chart, and backtest workflow.

Code example

Moving-average cross: MQL4 to thinkScript

These fragments show where the same signal starts in each API. They are not complete standalone programs; lifecycle setup, inputs, plots, and order handling still depend on the selected artifact.

MQL4 source fragment
double fast0 = iMA(NULL, 0, 10, 0, MODE_SMA, PRICE_CLOSE, 0);
double fast1 = iMA(NULL, 0, 10, 0, MODE_SMA, PRICE_CLOSE, 1);
double slow0 = iMA(NULL, 0, 20, 0, MODE_SMA, PRICE_CLOSE, 0);
double slow1 = iMA(NULL, 0, 20, 0, MODE_SMA, PRICE_CLOSE, 1);
bool longSignal = fast1 <= slow1 && fast0 > slow0;
thinkScript target fragment
def fast = Average(close, 10);
def slow = Average(close, 20);
plot longSignal = fast crosses above slow;

Workflow

A four-step migration path

Keep generation, target-platform validation, and behavior comparison as separate stages.

  1. 1

    Inventory the source behavior

    Separate calculations, plots, alerts, orders, external dependencies, and assumptions in an .mq4 Expert Advisor or custom indicator.

  2. 2

    Choose the target artifact

    Decide whether the result is a thinkScript study or strategy definition. This choice controls lifecycle methods and available APIs.

  3. 3

    Rewrite through target APIs

    Translate state, series, indicators, drawings, and orders into thinkorswim concepts instead of replacing function names.

  4. 4

    Validate behavior natively

    Paste into thinkScript Editor, save it as the correct study or strategy, add it to a chart, and inspect plots or the strategy report.

Manual decisions

Decisions code replacement cannot make

  • Identify the chart-calculation subset that fits a thinkScript study or strategy.
  • Rewrite loops and mutable buffers as supported definitions, recursion, or fold expressions.
  • Discard MT4 trade execution features that thinkScript chart strategies do not provide.

Limitations

What the draft cannot prove

  • MetaTrader 4 and thinkorswim do not share one execution, data, or order model, so behavior can change even when both versions compile.
  • Broker, symbol, session, timezone, history, and fill settings can change signals and backtest results on thinkorswim.
  • Pineify can generate and revise a thinkScript draft, but the target platform remains the authority for compilation, loading, backtesting, and runtime behavior.

Use cases

When this conversion is useful

  • Move an MT4 custom indicator into a thinkorswim study.
  • Visualize an EA signal without attempting to port its live execution engine.
  • Adapt simple MT4 alerts and plots to thinkorswim chart tools.

FAQ

MQL4 to thinkScript questions

Official references

Build the thinkScript draft with its native model in view

Bring the complete source and your artifact, timing, data, and order requirements. Validate the result in thinkorswim.

Open the thinkScript Coding AgentProduct details